DESCRIPTION: (Applicant's description) The elucidation of structure by conventional means can be time-consuming, especially with the complex highly functionalized compounds derived from natural sources. The computer offers opportunities for substantially greater productivity. SESAMI is a first generation, comprehensive program designed to directly reduce the collective spectral properties of an unknown, preferably to a single molecular structure, but to not more than a small number of structures which is exhaustive in nature (I.e., there is no other equally compatible structure). Enhanced productivity is achieved either way. In the latter case, the set of alternative structures is the starting point for the chemist and the assignment is readily make, since experienced chemists are proficient at identifying a correct structure from among a small number of alternatives. Although naturally occurring compounds commonly reach molecular weights of 1000 daltons or more, SESAMI's success has been largely limited to compounds up to 500 daltons. The project goal is a second generation program capable of routinely elucidating the structure of compounds with molecular weights up to 1000 daltons. Since the computational requirements of structure elucidation increase geometrically with increasing molecular weight, major improvements are required: substantial increases in the information content of the output of the spectrum interpretation programs, and significant increases in the efficiency of structure generation. In privately and publicly funded research and development laboratories, the need for computer-based tools to augment productivity in the elucidation of the structure of a broad spectrum of organic compounds has never been greater, particularly in drug discovery where complex compounds isolated form natural sources are of increasing interest.